package lab02.test28;

import java.util.InputMismatchException;
import java.util.Scanner;

public class  Test_28 {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);

            try {
                System.out.println("输入圆的半径：");
                double a = sc.nextDouble();
                double s = 3.14 * a * a;
                System.out.println("面积：" + s);

            } catch (InputMismatchException e) {
                System.out.println("你输入的数据不合法！");

            }

    }
}
